bpf: Roll back stream capacity when allocation fails

bpf_stream_push_str() accounts the string length before allocating a
stream element. If the allocation fails, the length remains charged even
though no element is queued and therefore cannot be released by a reader.
Repeated failures can exhaust the stream capacity permanently until the
BPF program is freed.

Refactor bpf_stream_release_capacity() to take a length so the consume
and release sides are symmetric, and use it to roll back the charge when
creating the stream element fails.

Fixes: 5ab154f1463a ("bpf: Introduce BPF standard streams")
Signed-off-by: Jianlin Shi <shijianlin11@foxmail.com>
Link: https://lore.kernel.org/r/c0ad7b18c59be6695fcc9e4e1200b2f4d5cbbea2.1787492521.git.shijianlin11@foxmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

0 files changed, 0 insertions, 0 deletions